Module delegate 

Parallel delegation primitive — spawn N isolated subagents with restricted toolsets and collect their summaries.

Port of _inspirations/hermes-agent/tools/delegate_tool.py. The key invariants:

• Isolation: child agents start with a fresh conversation — no parent history, own session-id-equivalent.
• Restricted toolset: caller specifies which tools the child may call. A default blocklist strips dangerous recursion paths (delegate, memory writes, user-interaction tools) at depth ≥ 1.
• Depth cap: max_depth = 2 (parent = 0, child = 1, no grandchildren) prevents infinite recursion.
• Bounded parallelism: up to max_concurrent children run at once via tokio::task::JoinSet.
• Best-effort: a child failure doesn’t abort the batch; the parent gets an error summary for that task and keeps going.

This module does NOT pull in a Python RPC bridge for code execution — that’s the 0.1.9 lift.

Structs

DelegateConfig

Top-level config for a batch delegation.

DelegateResult

Result from one child agent.

DelegateTask

Input to a single delegation.

Constants

DEFAULT_MAX_CONCURRENT

Default in-flight child limit per batch — matches hermes-agent’s max_concurrent_children.

DELEGATE_BLOCKED_TOOLS

Tools whose names match these strings are stripped from the child’s toolset. These are either recursion hazards (delegate) or cross-agent side effects (memory writes, user-facing messages). Caller-provided blocklists are merged with this default.

MAX_DEPTH

Maximum delegation depth (parent=0). Children cannot spawn grandchildren.

Functions

build_child_system_prompt

Build the child system prompt. Verbatim port of _inspirations/hermes-agent/tools/delegate_tool.py::_build_child_system_prompt — paraphrasing costs us the bench parity guarantee.

run_batch

Run a batch of delegations. Blocks until every child completes (success or failure). On depth exhaustion, returns an error immediately without spawning anything.

Type Aliases

ProviderFactory

Function that constructs a fresh provider for each child. Needed because Provider trait objects aren’t cloneable — each delegated child needs its own provider instance.

ToolsetFactory

Function that constructs a fresh toolset for each child. Same reason as ProviderFactory — Box<dyn Tool> isn’t cloneable.